This project is designed to assess the impact of an integrated Drug Court/treatment program on the behavior of drug-involved adult probationers, in comparison to different levels of drug testing or regular probation. More than 600 eligible probationers in Maricopa County (AZ) have been randomly assigned during the past year to the 4 experimental conditions (No testing, monthly testing, testing twice a week, and Drug Court/treatment), supported by a grant from the National Institute of Justice. That grant provides only for the collection and assessment of official record data 12 months after initial assignment. This proposal covers the administration and analysis of follow-up personal interviews and urine tests with the 600 subjects, and the collection and analysis of supplementary information from probation files, approximately 18 months after tee random assignment. The subjects include offenders charged with their first felony possession or use of illicit drugs. The Drug Court/treatment intervention involves court supervised behavioral contracts with each subject, providing) clear incentives to participate in appropriate levels of Out Patient Drug Free (OPDF) treatment. Preliminary observations of Drug Court participants and data from similar Drug Court programs suggests a high rate of treatment participation, and compliance with probation conditions, compared to regular probation or drug testing alone. Subjects will be paid $40 to come to a central office to complete the interview and drug test. The questionnaire will cover drug use, high- risk, criminal, and other behaviors during the 3 six-month periods following assignment to one of the program conditions. Analysis of this self-reported information will allow a much more complete and detailed assessment of each intervention's impacts, as opposed to relying on official records of arrests, drug tests and probation status alone. The well-implemented treatment conditions and strong experimental design provide a unique opportunity to compare the effectiveness of court supervised treatment with testing or regular supervision for drug involved probationers. This information will prove extremely valuable to criminal justice officials who must determine what types of offenders should be assigned to these various conditions.